1. Field of the Invention
This invention relates to a textile fabric for a three-dimensional shaping which is used principally as a reinforcer of a composite material for a structure having a configuration of a shell body of revolution or the like and also to a process of production of such a textile fabric.
2. Discussion of Background
In a composite material having reinforcing fiber orientation angles of 0 degree and 90 degrees, such characteristics as a coefficient of thermal conductivity and a coefficient of thermal expansion are represented by tensors of second order and the values of the characteristics are made isotropic, but it is known that the modulus of elasticity which is represented by a tensor of fourth order exhibits a remarkable anisotropy. It is theoretically determined that up to three axes of 0 degree and .+-.60 degrees are required in order to attain an isotropy in modulus of elasticity of a composite material. While it is not always required that the characteristics be isotropic, it is preferable that an arbitrary isotropy from a one directional reinforcer to an isotropic reinforcer can be realized in order to make use of the advantage of a composite material t possible to design characteristics of the mater order to realize the isotropy in modulus of elasticity, a triaxial flat plane fabric having orientation angles of 0 degree and .+-.60 degrees and an equipment for production of the same have been developed and sold by Barber Colman Co. (U.S. Pat. No. 4,040,451 and U.S. Pat. No. 4,105,052) in addition to fabrics of a plain weave and a satin weave as reinforcers for a composite material for a structure.
Such a flat plane fabric is effective to produce a composite material of a configuration of a curved plane plate having a curved flat surface or a developable surface. However, where it is to be used for a general curved surface, it must be either distorted in orientation axes thereof or a reinforcing fabric must be patched thereto. Accordingly, deterioration in characteristics of the flat plane fabric such as strength, rigidity and accuracy in dimension cannot be avoided. Accordingly, it is desired to directly produce, as a reinforcer for a composite material, a textile fabric having a texture which can be readily deformed into a three-dimensional configuration without causing special changes in three-dimensional configuration or orientation angles. However, while such textile fabrics have been realized with some plain weaves and some knit textures, a triaxial textile fabric having orientation angles of 0 degree and .+-.60 degrees wherein the modulus of elasticity can be made isotropic has not yet been developed.
Conventionally, such measures are also taken that a suitable number of prepreg sheets each formed by arranging reinforcing fibers in one direction and impregnating the reinforcing fibers with uncured resin material are placed in layers with their orientations displaced by a required angle from each other. However, if the textile fabric thus produced is applied to a curved plane body, then some distortion will appear in orientation angles of the textile fabric, or in some cases, patching may be required, similarly as in the case of the flat plane fabric which is used as a reinforcer described hereinabove.